Metabolomics Analysis
Joeri Jongbloets
March 09 2020
Exercise 1: Preparation
In the load_data chunk we need to load all the data we will need for the analysis. We have 2 data sources:
design: maps sample_ids to the conditions of the experimentmetabolomics: contains the measured intensities of each feature and mapping of metabolomics samples to sample_id.
The data is stored respectively in 3 data.frames: df.design, df.metabolomics.raw and df.metabolomics.design.
Exercise 1.1
First thing to do when encountering a new dataset is to look at it’s shape and properties.
## Observations: 28,950
## Variables: 11
## $ bucket <chr> "344.07941 Da 18.36 s", "344.07941 Da 18.36 s", "344.…
## $ RT <dbl> 0.31, 0.31, 0.31, 0.31, 0.31, 0.31, 0.63, 0.63, 0.63,…
## $ mz_ratio <dbl> 345.0867, 345.0867, 345.0867, 345.0867, 345.0867, 345…
## $ Name <chr> NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, NA, N…
## $ Formula <chr> "C20H12N2O4", "C20H12N2O4", "C20H12N2O4", "C20H12N2O4…
## $ phase <chr> "apolar", "apolar", "apolar", "apolar", "apolar", "ap…
## $ mass <dbl> 344.0794, 344.0794, 344.0794, 344.0794, 344.0794, 344…
## $ charge <dbl> 0.9970811, 0.9970811, 0.9970811, 0.9970811, 0.9970811…
## $ metabolomics_id <chr> "202002_TTP_SILS2665_RA_1_1 _merged_", "202002_TTP_SI…
## $ value <dbl> 10066, 9210, 9564, 8882, 9346, 8106, 3996, 4116, 4132…
## $ value_log10 <dbl> 4.002900, 3.964307, 3.980685, 3.948560, 3.970672, 3.9…Question 1.1
What is in data.frame and what do you think is the meaning of each column? Is the data in a tidy format?
Feature Statistics
As you might have notice, some of the features have a formula and/or a label associated to it but other don’t. In addition, there are features that have the same formula and/or label. Create a figure showing the percentage of features with a formula and with a name for each phase and a table showing the total number of features and with names and formulas and how many of those are unique for each phase.
| phase | total_count | n_formula | n_uniq_formula | n_label | n_uniq_label |
|---|---|---|---|---|---|
| apolar | 11742 | 8460 | 1237 | 108 | 16 |
| polar | 17208 | 8718 | 1240 | 660 | 89 |
Distribution of Raw Values
Number of Zeros
Total Intensity
MA Plots
Normalizing
df.metabolomics <- df.metabolomics.raw %>%
group_by(phase, bucket) %>%
mutate(
value_norm = ifelse(value <= 0, min(value[value > 0], na.rm = T) / 2, value),
value_norm_log10 = log10(value_norm)
) %>%
group_by(phase)
Total Intensity
MA Plots
PCA
Loadings of PC 1
Most down-regulated metabolites of PC 1:
| phase | bucket | loading |
|---|---|---|
| apolar | 870.56984 Da 803.03 s | -0.1775119 |
| apolar | 892.54105 Da 803.03 s | -0.1252981 |
| apolar | 551.42610 Da 842.78 s | -0.1207451 |
| apolar | 396.00441 Da 41.68 s | -0.1011673 |
| apolar | 886.56398 Da 850.98 s | -0.0993336 |
| apolar | 792.56643 Da 505.34 s | -0.0991903 |
| apolar | 349.96167 Da 41.67 s | -0.0961210 |
| apolar | 1052.52432 Da 807.07 s | -0.0849786 |
| apolar | 381.98812 Da 41.95 s | -0.0791344 |
| apolar | 335.94565 Da 41.39 s | -0.0776370 |
| polar | 202.16809 Da 35.67 s | -0.0963273 |
| polar | 545.16130 Da 170.88 s | -0.0959617 |
| polar | 143.09457 Da 35.95 s | -0.0698610 |
| polar | 551.17860 Da 52.61 s | -0.0688578 |
| polar | 1389.01032 Da 439.32 s | -0.0683566 |
| polar | 279.13232 Da 47.75 s | -0.0671033 |
| polar | 1275.92760 Da 432.91 s | -0.0634677 |
| polar | 491.44838 Da 1179.75 s | -0.0631968 |
| polar | 505.17065 Da 53.87 s | -0.0624037 |
| polar | 198.08906 Da 403.32 s | -0.0621769 |
Most up-regulated metabolites of PC 1:
| phase | bucket | loading |
|---|---|---|
| apolar | 195.05665 Da 40.87 s | 0.2267028 |
| apolar | 412.09570 Da 40.31 s | 0.1440448 |
| apolar | 175.96327 Da 18.43 s | 0.1026345 |
| apolar | 467.00597 Da 39.82 s | 0.1018463 |
| apolar | 131.97352 Da 18.49 s | 0.0874081 |
| apolar | 243.95081 Da 24.01 s | 0.0765888 |
| apolar | 379.92616 Da 20.53 s | 0.0744116 |
| apolar | 311.93825 Da 20.61 s | 0.0734376 |
| apolar | 243.95122 Da 70.97 s | 0.0706117 |
| apolar | 379.92574 Da 33.46 s | 0.0665436 |
| polar | 195.05672 Da 46.20 s | 0.1339618 |
| polar | 780.22632 Da 47.97 s | 0.1121678 |
| polar | 684.08708 Da 50.27 s | 0.1023996 |
| polar | 330.11082 Da 47.20 s | 0.0893236 |
| polar | 343.95574 Da 45.53 s | 0.0657282 |
| polar | 443.02423 Da 50.64 s | 0.0651033 |
| polar | 545.16084 Da 190.07 s | 0.0634573 |
| polar | 218.04115 Da 45.53 s | 0.0630638 |
| polar | 507.04174 Da 50.76 s | 0.0581213 |
| polar | 553.82966 Da 26.74 s | 0.0551570 |
Heatmap
Another useful tool is to plot the expression levels in a heatmap.
T-test
Volcano Plot
List of Significant Metabolites
Finally print a table with all interesting buckets.
Polar Phase
| phase | bucket | Name | Formula | logFC | p.value | padj |
|---|---|---|---|---|---|---|
| polar | 1389.01032 Da 439.32 s | NA | C55H112N44 | -4.555173 | 0.0000000 | 0.0000000 |
| polar | 1275.92760 Da 432.91 s | NA | C70H134NO14PS | -4.215218 | 0.0000000 | 0.0000000 |
| polar | 505.17065 Da 53.87 s | NA | C13H36N3O13PS | -4.305261 | 0.0000000 | 0.0000000 |
| polar | 113.08366 Da 47.02 s | NA | NA | 3.256798 | 0.0000000 | 0.0000000 |
| polar | 248.97570 Da 51.41 s | NA | NA | 3.654155 | 0.0000000 | 0.0000000 |
| polar | 162.05319 Da 53.18 s | NA | C6H10O5 | -3.078141 | 0.0000000 | 0.0000000 |
| polar | 99.06825 Da 48.34 s | NA | C5H9NO | 3.753294 | 0.0000000 | 0.0000000 |
| polar | 324.10542 Da 52.62 s | NA | C17H16N4OS | -3.165424 | 0.0000000 | 0.0000000 |
| polar | 557.08069 Da 53.14 s | NA | NA | -3.012152 | 0.0000000 | 0.0000000 |
| polar | 135.05421 Da 46.92 s | NA | NA | -4.030530 | 0.0000000 | 0.0000000 |
| polar | 653.80118 Da 35.63 s | NA | C15H6N6O8S8 | -2.936358 | 0.0000000 | 0.0000000 |
| polar | 162.05294 Da 48.25 s | NA | C6H10O5 | -4.163746 | 0.0000000 | 0.0000000 |
| polar | 307.01122 Da 49.47 s | NA | C8H9N3O8S | -2.829478 | 0.0000000 | 0.0000000 |
| polar | 118.02789 Da 46.85 s | NA | C5H2N4 | -2.469851 | 0.0000000 | 0.0000000 |
| polar | 218.04115 Da 45.53 s | NA | C5H10N6S2 | 4.446394 | 0.0000000 | 0.0000000 |
| polar | 195.05672 Da 46.20 s | 2-_N-morpholino_ethanesulfonic acid | C6H13NO4S | 9.585964 | 0.0000000 | 0.0000000 |
| polar | 281.91637 Da 34.82 s | NA | C8H2N4S4 | -2.654038 | 0.0000000 | 0.0000000 |
| polar | 684.08708 Da 50.27 s | NA | C19H28N10O10S4 | 7.063308 | 0.0000000 | 0.0000000 |
| polar | 364.09957 Da 47.62 s | NA | C19H16N4O2S | -2.058190 | 0.0000000 | 0.0000000 |
| polar | 851.81735 Da 35.69 s | NA | NA | 2.005496 | 0.0000000 | 0.0000000 |
| polar | 443.02423 Da 50.64 s | NA | C21H10N5O3PS | 4.554010 | 0.0000000 | 0.0000000 |
| polar | 54.04650 Da 51.02 s | NA | NA | -2.164031 | 0.0000000 | 0.0000000 |
| polar | 80.96480 Da 48.87 s | NA | NA | 2.927677 | 0.0000000 | 0.0000000 |
| polar | 165.04569 Da 42.94 s | NA | NA | -2.108192 | 0.0000000 | 0.0000000 |
| polar | 551.17860 Da 52.61 s | NA | C24H42NO3PS4 | -4.568843 | 0.0000000 | 0.0000000 |
| polar | 182.20346 Da 1169.50 s | NA | C13H26 | -2.225089 | 0.0000000 | 0.0000000 |
| polar | 506.42937 Da 1163.27 s | NA | C27H58N2O6 | -2.044209 | 0.0000000 | 0.0000000 |
| polar | 330.11082 Da 47.20 s | NA | C19H14N4O2 | 6.473521 | 0.0000000 | 0.0000000 |
| polar | 666.22332 Da 65.72 s | NA | C17H44N6O17P2 | -2.186947 | 0.0000000 | 0.0000000 |
| polar | 153.98977 Da 215.00 s | NA | C6H2O5 | -3.892951 | 0.0000000 | 0.0000000 |
| polar | 135.05435 Da 47.06 s | Adenine | C5H5N5 | -2.533111 | 0.0000000 | 0.0000000 |
| polar | 468.37287 Da 1179.28 s | NA | C28H53O3P | -3.342201 | 0.0000000 | 0.0000000 |
| polar | 505.42821 Da 1174.94 s | NA | C35H55NO | -2.521896 | 0.0000000 | 0.0000000 |
| polar | 254.09980 Da 49.53 s | NA | C9H18O8 | -3.468359 | 0.0000000 | 0.0000000 |
| polar | 491.44838 Da 1179.75 s | NA | C27H61N3O2S | -2.660801 | 0.0000000 | 0.0000000 |
| polar | 202.16809 Da 35.67 s | NA | C10H22N2O2 | -2.633177 | 0.0000000 | 0.0000000 |
| polar | 952.76234 Da 33.05 s | NA | C47H120N2O3S6 | -2.202088 | 0.0000000 | 0.0000000 |
| polar | 64.00597 Da 46.78 s | NA | NA | -2.522702 | 0.0000000 | 0.0000000 |
| polar | 279.13232 Da 47.75 s | NA | C12H25NO2S2 | -4.567685 | 0.0000000 | 0.0000000 |
| polar | 143.09457 Da 35.95 s | NA | C7H13NO2 | -2.300674 | 0.0000000 | 0.0000000 |
| polar | 302.12622 Da 407.64 s | NA | C8H22N4O6S | -2.043212 | 0.0000000 | 0.0000000 |
| polar | 84.09360 Da 1174.56 s | NA | NA | -2.219466 | 0.0000000 | 0.0000000 |
| polar | 446.39040 Da 1170.36 s | NA | C17H50N8O5 | -2.146587 | 0.0000000 | 0.0000000 |
| polar | 302.06080 Da 66.17 s | NA | C8H18N2O6S2 | 2.066950 | 0.0000000 | 0.0000000 |
| polar | 211.05125 Da 67.62 s | NA | C6H13NO5S | 2.214530 | 0.0000000 | 0.0000001 |
| polar | 233.03331 Da 68.81 s | NA | C12H11NS2 | 2.218716 | 0.0000000 | 0.0000001 |
| polar | 780.22632 Da 47.97 s | NA | C27H53N6O8PS5 | 8.985664 | 0.0000000 | 0.0000001 |
| polar | 324.10409 Da 67.10 s | NA | C17H24S3 | -2.304131 | 0.0000000 | 0.0000001 |
| polar | 309.96791 Da 67.81 s | NA | C8H3N6O4PS | 2.248768 | 0.0000000 | 0.0000001 |
| polar | 418.57380 Da 48.36 s | NA | NA | 2.127005 | 0.0000000 | 0.0000002 |
| polar | 255.96926 Da 300.67 s | NA | NA | 2.287815 | 0.0000000 | 0.0000002 |
| polar | 440.14031 Da 52.94 s | NA | C15H20N8O8 | 2.329616 | 0.0000000 | 0.0000003 |
| polar | 636.12403 Da 101.36 s | NA | C17H44N6O3S8 | -2.389652 | 0.0000000 | 0.0000003 |
| polar | 186.01639 Da 214.63 s | NA | C7H6O6 | -4.846004 | 0.0000000 | 0.0000004 |
| polar | 636.12253 Da 100.16 s | NA | C24H35N2O10P3S | -2.006664 | 0.0000000 | 0.0000004 |
| polar | 312.13616 Da 50.15 s | NA | C19H20O4 | 2.413914 | 0.0000001 | 0.0000007 |
| polar | 975.28149 Da 48.06 s | NA | C33H49N23OS6 | 2.558661 | 0.0000001 | 0.0000010 |
| polar | 86.03658 Da 36.94 s | NA | NA | -2.607038 | 0.0000001 | 0.0000010 |
| polar | 85.05253 Da 37.75 s | NA | C4H7NO | -2.388347 | 0.0000001 | 0.0000010 |
| polar | 211.05153 Da 67.98 s | NA | C6H13NO5S | 2.855304 | 0.0000003 | 0.0000023 |
| polar | 195.45403 Da 48.06 s | NA | NA | 2.859702 | 0.0000004 | 0.0000028 |
| polar | 310.12002 Da 45.46 s | NA | C11H22N2O6S | 2.695707 | 0.0000006 | 0.0000039 |
| polar | 195.05656 Da 124.38 s | NA | C6H13NO4S | 2.878740 | 0.0000006 | 0.0000041 |
| polar | 424.11927 Da 45.00 s | NA | C13H32N2O5S4 | 3.067000 | 0.0000007 | 0.0000043 |
| polar | 342.11236 Da 47.50 s | NA | C19H18O6 | 4.972082 | 0.0000007 | 0.0000046 |
| polar | 313.56890 Da 46.09 s | NA | NA | 2.775471 | 0.0000009 | 0.0000057 |
| polar | 753.53621 Da 865.22 s | NA | NA | -3.140059 | 0.0000009 | 0.0000059 |
| polar | 72.02134 Da 43.52 s | NA | C3H4O2 | 2.305519 | 0.0000011 | 0.0000067 |
| polar | 390.67583 Da 47.24 s | NA | NA | 3.266031 | 0.0000012 | 0.0000072 |
| polar | 732.22414 Da 45.42 s | NA | C19H41N16O7PS3 | 3.195876 | 0.0000015 | 0.0000092 |
| polar | 107.98852 Da 67.88 s | NA | NA | 3.430137 | 0.0000016 | 0.0000097 |
| polar | 110.07262 Da 403.89 s | NA | NA | -2.076471 | 0.0000018 | 0.0000106 |
| polar | 197.03605 Da 160.38 s | NA | NA | 3.360882 | 0.0000018 | 0.0000107 |
| polar | 537.17417 Da 52.41 s | NA | C13H40N5O9PS3 | 5.490517 | 0.0000018 | 0.0000109 |
| polar | 684.08553 Da 49.48 s | NA | C25H9N20O4P | 3.249192 | 0.0000019 | 0.0000113 |
| polar | 192.02681 Da 83.77 s | Isocitric acid | C6H8O7 | -2.885696 | 0.0000024 | 0.0000139 |
| polar | 626.16820 Da 185.51 s | NA | C19H47O12PS4 | 3.243613 | 0.0000025 | 0.0000142 |
| polar | 569.14799 Da 188.92 s | NA | C27H27N3O9S | 3.526546 | 0.0000041 | 0.0000222 |
| polar | 293.11182 Da 74.41 s | NA | C12H23NO3S2 | -2.458849 | 0.0000050 | 0.0000262 |
| polar | 474.01089 Da 47.04 s | NA | NA | -2.285457 | 0.0000053 | 0.0000279 |
| polar | 424.14514 Da 52.69 s | NA | C16H32N4OS4 | 3.730984 | 0.0000064 | 0.0000330 |
| polar | 424.14674 Da 52.13 s | NA | C13H33N2O7PS2 | 4.566647 | 0.0000070 | 0.0000356 |
| polar | 507.04174 Da 50.76 s | NA | C21H5N11O6 | 4.323988 | 0.0000071 | 0.0000358 |
| polar | 549.85850 Da 29.05 s | NA | NA | 2.003548 | 0.0000080 | 0.0000401 |
| polar | 135.98121 Da 29.42 s | NA | NA | 2.214074 | 0.0000086 | 0.0000428 |
| polar | 153.12665 Da 47.66 s | NA | C8H15N3 | -2.154987 | 0.0000128 | 0.0000614 |
| polar | 521.19632 Da 52.29 s | NA | C32H23N7O | -2.456207 | 0.0000130 | 0.0000618 |
| polar | 335.08973 Da 101.06 s | NA | C9H23NO8P2 | -2.062132 | 0.0000185 | 0.0000855 |
| polar | 535.03645 Da 50.76 s | NA | C16H6N15O6P | 3.506536 | 0.0000206 | 0.0000924 |
| polar | 225.03063 Da 215.72 s | NA | C6H11NO6S | 2.029406 | 0.0000227 | 0.0000990 |
| polar | 187.19382 Da 422.38 s | NA | C11H25NO | 3.308400 | 0.0000287 | 0.0001207 |
| polar | 330.11118 Da 45.92 s | NA | C19H22OS2 | 3.578154 | 0.0000300 | 0.0001246 |
| polar | 195.07332 Da 46.94 s | NA | NA | 4.877764 | 0.0000347 | 0.0001397 |
| polar | 553.82966 Da 26.74 s | NA | NA | 3.317413 | 0.0000361 | 0.0001438 |
| polar | 128.04615 Da 784.34 s | NA | NA | -2.470722 | 0.0000529 | 0.0001990 |
| polar | 429.08512 Da 235.88 s | NA | C24H15NO7 | -4.132066 | 0.0000562 | 0.0002090 |
| polar | 228.10056 Da 337.15 s | NA | C12H20S2 | -2.283454 | 0.0000576 | 0.0002128 |
| polar | 144.00508 Da 164.12 s | NA | NA | -2.159048 | 0.0000594 | 0.0002182 |
| polar | 689.03853 Da 100.75 s | NA | NA | -2.455262 | 0.0000633 | 0.0002308 |
| polar | 271.09782 Da 40.14 s | NA | C12H18NO4P | -2.257001 | 0.0000674 | 0.0002434 |
| polar | 356.12601 Da 54.83 s | NA | C20H20O6 | 5.769899 | 0.0000786 | 0.0002778 |
| polar | 412.04905 Da 591.83 s | NA | NA | -2.141486 | 0.0000828 | 0.0002909 |
| polar | 343.95574 Da 45.53 s | NA | NA | 4.119137 | 0.0000856 | 0.0002987 |
| polar | 315.10435 Da 40.18 s | NA | C16H17N3O2S | 3.475439 | 0.0001049 | 0.0003585 |
| polar | 565.83665 Da 29.00 s | NA | C13H3N4O12PS4 | 2.313891 | 0.0001126 | 0.0003827 |
| polar | 406.27013 Da 988.50 s | NA | C13H34N12OS | -2.892391 | 0.0001250 | 0.0004199 |
| polar | 353.01730 Da 49.08 s | NA | C10H15N3O5S3 | -2.922707 | 0.0001300 | 0.0004334 |
| polar | 339.35181 Da 1143.69 s | NA | NA | -2.066433 | 0.0001305 | 0.0004341 |
| polar | 310.25076 Da 1097.05 s | NA | C19H34O3 | -2.065588 | 0.0001410 | 0.0004631 |
| polar | 197.11625 Da 49.80 s | NA | C9H15N3O2 | -2.190925 | 0.0001495 | 0.0004890 |
| polar | 107.98851 Da 151.00 s | NA | NA | 3.109918 | 0.0001550 | 0.0005045 |
| polar | 81.98175 Da 1174.56 s | NA | NA | -3.942862 | 0.0001720 | 0.0005488 |
| polar | 407.90954 Da 42.95 s | NA | NA | 2.276425 | 0.0002041 | 0.0006399 |
| polar | 594.18444 Da 187.01 s | NA | C43H22N4 | -2.474780 | 0.0002277 | 0.0007060 |
| polar | 398.14052 Da 41.90 s | NA | C11H32N2O7P2S | -2.156689 | 0.0002412 | 0.0007430 |
| polar | 338.11726 Da 129.06 s | NA | NA | -2.279316 | 0.0003163 | 0.0009459 |
| polar | 74.00025 Da 586.69 s | NA | NA | -2.020343 | 0.0003212 | 0.0009545 |
| polar | 215.11621 Da 403.33 s | NA | C10H17NO4 | -2.886132 | 0.0003425 | 0.0010097 |
| polar | 576.13728 Da 560.21 s | NA | NA | -2.372809 | 0.0003452 | 0.0010165 |
| polar | 56.06225 Da 1178.52 s | NA | NA | -2.653122 | 0.0004098 | 0.0011752 |
| polar | 159.12589 Da 38.85 s | NA | NA | -2.408645 | 0.0004291 | 0.0012246 |
| polar | 351.08872 Da 183.84 s | NA | C7H13N9O8 | -3.699313 | 0.0005237 | 0.0014622 |
| polar | 270.14690 Da 581.44 s | NA | C14H22O5 | -2.294280 | 0.0008794 | 0.0023354 |
| polar | 706.16532 Da 1050.14 s | NA | C30H39N6O4PS4 | -2.127643 | 0.0014082 | 0.0035646 |
| polar | 143.16765 Da 179.80 s | NA | C9H21N | 2.617752 | 0.0014405 | 0.0036369 |
| polar | 162.99232 Da 30.05 s | NA | NA | 3.652277 | 0.0017044 | 0.0041816 |
| polar | 130.99596 Da 29.67 s | NA | NA | 2.348092 | 0.0019884 | 0.0048043 |
| polar | 174.53774 Da 211.84 s | NA | NA | -2.595379 | 0.0026957 | 0.0063143 |
| polar | 311.55770 Da 52.79 s | NA | NA | 2.607354 | 0.0027307 | 0.0063777 |
| polar | 56.06226 Da 1166.73 s | NA | NA | -2.157214 | 0.0027661 | 0.0064498 |
| polar | 835.84772 Da 33.22 s | NA | C25H14O21P6 | 2.707956 | 0.0029057 | 0.0067014 |
| polar | 774.52839 Da 1183.19 s | NA | C32H75N10O7PS | 2.806289 | 0.0033151 | 0.0075219 |
| polar | 641.08784 Da 50.18 s | NA | C14H32N11O6PS5 | 2.840442 | 0.0034151 | 0.0077244 |
| polar | 312.26765 Da 1181.50 s | NA | NA | 2.985652 | 0.0042354 | 0.0092726 |
| polar | 611.17805 Da 1184.30 s | NA | C28H38NO8PS2 | 3.145050 | 0.0042868 | 0.0093637 |
Apolar Phase
| phase | bucket | Name | Formula | logFC | p.value | padj |
|---|---|---|---|---|---|---|
| apolar | 467.00597 Da 39.82 s | NA | C20H9N3O9S | 4.000910 | 0.0000000 | 0.0000000 |
| apolar | 1052.52432 Da 807.07 s | NA | C65H84N2S5 | -2.084333 | 0.0000000 | 0.0000000 |
| apolar | 792.56643 Da 505.34 s | NA | NA | -2.839855 | 0.0000000 | 0.0000000 |
| apolar | 870.56984 Da 803.03 s | NA | C51H84O7P2 | -6.365147 | 0.0000000 | 0.0000001 |
| apolar | 191.04414 Da 41.28 s | NA | NA | 2.258838 | 0.0000000 | 0.0000002 |
| apolar | 892.54105 Da 803.03 s | NA | C52H81N2O4PS2 | -4.162065 | 0.0000001 | 0.0000004 |
| apolar | 244.90652 Da 77.09 s | NA | NA | -2.165518 | 0.0000001 | 0.0000009 |
| apolar | 195.05665 Da 40.87 s | 2-_N-morpholino_ethanesulfonic acid | C6H13NO4S | 8.600611 | 0.0000003 | 0.0000020 |
| apolar | 412.09570 Da 40.31 s | NA | C11H24N8OS4 | 5.166741 | 0.0000017 | 0.0000080 |
| apolar | 349.96167 Da 41.67 s | NA | NA | -2.944103 | 0.0000252 | 0.0000832 |
| apolar | 886.56398 Da 850.98 s | NA | C34H66N26OS | -2.829708 | 0.0000922 | 0.0002589 |
| apolar | 396.00441 Da 41.68 s | NA | NA | -2.234544 | 0.0001141 | 0.0003107 |
| apolar | 381.98812 Da 41.95 s | NA | C18H7O8P | -2.782766 | 0.0001375 | 0.0003630 |
| apolar | 551.42610 Da 842.78 s | NA | NA | -3.244671 | 0.0003743 | 0.0008795 |
| apolar | 335.94565 Da 41.39 s | NA | NA | -2.142793 | 0.0007243 | 0.0015716 |
Export
## `mutate_if()` ignored the following grouping variables:
## Columns `phase`, `bucket`T-test results were exported to ./data/processed/metabolomics/20200309_metabolomics_ttest.csv